The present invention relates to a new and improved key-cutting device which is used to cut one or more notches in a key blank
A key cutting device for cutting one or more notches in a key blank is disclosed in U.S. Pat. No. 3,633 451 issued Jan. 11, 1972 and entitled "Key-Cutting Machine With Coordinated Positioning and Cutting Movements". The key-cutting device disclosed in this patent includes a holder for holding a key blank in which notches are to be cut. The holder is movable between initial and cutting positions. A cutter is moved relative to the holder to cut notches in the key blank held by the holder when the holder is in a cutting position. An actuator performs the dual functions of first moving the holder to a cutting position and then moving the cutter to notch the key blank.
The actuator includes a saddle assembly having a saddle or member which pivots relative to a base of the key-cutting device to move the holder from the initial position to the cutting position. One end of a leaf spring is connected to the saddle member. A set screw extends through the saddle member and engages the leaf spring. After the key blank holder has been moved to a cutting position, continued operation of the actuator deflects the leaf spring about the end of the set screw.
During storage and/or use of the key-cutting device disclosed in the aforementioned U.S. Pat. No. 3,633,451, the leaf spring weakens. As the leaf spring weakens, the depths of cut by the punch may become shallow and erratic. The leaf spring will eventually weaken to a point where a key formed by notching a key blank will no longer open a lock. At this time, the saddle tension must be reset by turning the adjusting screw on top of the saddle member.
After the reset adjustment has been done several times, the saddle spring will break and a replacement is needed. If the set screw is turned too far in, that is, over-adjusted, a trigger on the key-cutting device will stick. The weakening of the saddle spring greatly increases the tolerances to which notches can be cut in a key blank. The operating life of the saddle assembly in a heavily used key-cutting device is approximately one month.